Murray served for the match at 5-4 in the second set, but, instead, went on to
lose the stanza via tiebreak.

The Olympic gold medalist and Wimbledon runner-up Murray suffered a loss for a
third time in the last month after holding a match point.

Second-seeded Novak Djokovic was a second-round loser here on Wednesday.

Meanwhile, wild card and veteran French crowd favorite Michael Llodra upended
the seventh-seeded del Potro 6-4, 6-3 in only 69 minutes. A weary del Potro
was fresh off his back-to-back titles in Vienna and Basel. He stunned Roger
Federer in the final at the Swiss Indoors event in Federer's native Basel last
week.

Del Potro, like Murray, will be part of next week's elite eight-player field
at the ATP World Tour Finals in London.

Tipsarevic will battle Janowicz on Friday, while Querrey will take on Llodra.

Also, Frenchman Gilles Simon reached the quarterfinals via walkover when
15th-seeded Japanese Kei Nishikori pulled out of the event due to an ankle
injury. Simon should have his hands full with Berdych on Friday.